Hi Nick, These threads are spawned with each zookeeper client handle. As soon as you create a zookeeper client object these threads are spawned.
Are yu creating too many zookeeper client objects in your application? Htanks mahadev On 5/20/10 11:30 AM, "Nick Bailey" <nicholas.bai...@rackspace.com> wrote: > Hey guys, > > Question regarding zookeeper's EventThread and SendThread. I'm not quite sure > what these are used for but a stacktrace of our client application contains > lines similar to > > "pool-2-thread-20-EventThread" daemon prio=10 tid=0x00002aac3cb29c00 nid=0x75d > waiting on condition [0x000000006b080000..0x000000006b080b10] > java.lang.Thread.State: WAITING (parking) > at sun.misc.Unsafe.park(Native Method) > - parking to wait for <0x00002aab1f577250> (a > java.util.concurrent.locks.AbstractQueuedSynchronizer$ConditionObject) > at java.util.concurrent.locks.LockSupport.park(LockSupport.java:158) > at > java.util.concurrent.locks.AbstractQueuedSynchronizer$ConditionObject.await(Ab > stractQueuedSynchronizer.java:1925) > at > java.util.concurrent.LinkedBlockingQueue.take(LinkedBlockingQueue.java:358) > at > org.apache.zookeeper.ClientCnxn$EventThread.run(ClientCnxn.java:414) > > "pool-2-thread-20-SendThread" daemon prio=10 tid=0x00002aac3c35d400 nid=0x75c > runnable [0x0000000070ede000..0x0000000070edeb90] > java.lang.Thread.State: RUNNABLE > at sun.nio.ch.EPollArrayWrapper.epollWait(Native Method) > at sun.nio.ch.EPollArrayWrapper.poll(EPollArrayWrapper.java:215) > at sun.nio.ch.EPollSelectorImpl.doSelect(EPollSelectorImpl.java:65) > at sun.nio.ch.SelectorImpl.lockAndDoSelect(SelectorImpl.java:69) > - locked <0x00002aab1f571d08> (a sun.nio.ch.Util$1) > - locked <0x00002aab1f571cf0> (a > java.util.Collections$UnmodifiableSet) > - locked <0x00002aab1f5715b8> (a sun.nio.ch.EPollSelectorImpl) > at sun.nio.ch.SelectorImpl.select(SelectorImpl.java:80) > at org.apache.zookeeper.ClientCnxn$SendThread.run(ClientCnxn.java:921) > > There are pairs of threads ranging from thread-1 to thread-50 and also > multiple pairs of these threads. As in pool-2-thread-20-SendThread is the > name of multiple threads in the trace. I'm debugging some load issues with > our system and am suspicious that the large amount of zookeeper threads is > contributing. Would anyone be able to elaborate on the purpose of these > threads and how they are spawned? > > Thanks, > > Nick Bailey > Rackspace Hosting > Software Developer, Email & Apps > nicholas.bai...@rackspace.com >
